This invention relates to a turbo-electric marine power plant which includes a variable-speed heavy gas turbine, a synchronous propulsion generator coupled mechanically with the gas turbine and a synchronous or asynchronous propulsion motor coupled electrically with the propulsion generator. The propulsion motor drives a fixed propeller by means of a propeller shaft. The drive is effected by frequency regulation down to a minimum turbine rpm and by means of slip regulation below the minimum turbine rpm.
Turbo-electric marine power plants which have a heavy gas turbine as prime mover are known. In such a power plant the turbine is connected mechanically with the synchronous propulsion generator. The synchronous generator supplies current to the propulsion motor which may be of the synchronous or asynchronous type. In such an arrangement the propulsion generator and the propulsion motor constitute a drive substitute in the form of an "electric shaft". Since, on the one hand, the turbine runs continuously with the nominal rpm and is, on the other hand, not reversible, the propeller has to be of the adjustable type to make possible a change in the travelling speed of the ship and a reversal of the propelling force by virtue of changing the angular setting of the propeller blades. In this connection reference is made to the periodical SHIP-BUILDING AND SHIPPING RECORD of Feb. 16, 1973 pages 15 - 19 entitled: "General Electric's Heavy Duty Gasturbine/Electric Propulsion System". It is a disadvantage of such an arrangement that the output is, for econimical consideration, limited to approximately 40,000 HP.
In another known embodiment of such power plant there is used a slip clutch in connection with a fixed propeller; thus, the travelling speed of the ship and the reversal of propulsion are controlled by means of the slip clutch.